TERRAFORMING TERRA
We discuss and comment on the role agriculture will play in the containment of the CO2 problem and address protocols for terraforming the planet Earth.
A model farm template is imagined as the central methodology. A broad range of timely science news and other topics of interest are commented on.

Tuesday, December 28, 2010

Biological Hydrogen Production

I suspect that there is more to
this story than meets the eye.However,
in the meantime we have confirmation of hydrogen production.The really good news is that this gives us a natural
way to produce gaseous hydrogen at modest cost and that is surely good news.

The next question is whether this
is a cost effective way to convert solar energy directly into hydrogen.If that were to work out, the advantage is
huge.Close to utilization the
advantages of hydrogen are high.It only
becomes a problem if we decide to ship it.

Even converting hydrogen into
electricity is a pretty efficient process in the right circumstances.

This may all stall in the
details, but at least we now have the option to play with.

Cyanobacterium gives off hydrogen as by-product of day-to-day
processes.

December 14, 2010

By Katharine Sanderson

A seemingly unremarkable ocean microbe turns out to be a multitasker --
it can not only photosynthesize, but can also produce large amounts of
hydrogen, opening up a potential way to make the gas cheaply for fuel.

The single-celled cyanobacteriumCyanothece 51142 can make hydrogen in
air, Himadri Pakrasi of WashingtonUniversity in St
Louis, Missouri, and
his colleagues report in Nature Communications1. Until now, the only organisms
known to make hydrogen could only produce it in an oxygen-free environment --
making it a potentially expensive process to scale-up.

Cyanothece 51142 was discovered in 1993, off the coast of Texas, by
Louis Sherman of Purdue University in West Lafayette, Indiana, a co-author on
the study. Pakrasi later discovered that the bacterium has a two-stage daily
cycle. During the day it undergoes photosynthesis, using sunlight and carbon
dioxide to make oxygen and branching chains of glucose molecules called
glycogen. When the Sun goes down, the microbe's nitrogenase enzyme kicks into
action, using the energy stored in the glycogen to fix nitrogen from the air into
ammonia. Hydrogen is formed as a by-product.

The two mechanisms are different in that photosynthesis is an aerobic
process -- one that requires oxygen -- whereas nitrogen fixation, and,
consequently, hydrogen production, can take place only anaerobically, because
contact with oxygen destroys the nitrogenase enzyme. But Cyanothece 51142
manages to fix nitrogen even in the presence of atmospheric oxygen by burning
cellular oxygen to produce energy. Because no photosynthesis is taking place,
the bacterium uses up its cellular oxygen so that the nitrogenase enzyme is
effectively in a largely oxygen-free environment.

Rhythmic reactions

Cyanothece 51142 has a natural circadian rhythm that allows it to be
'trained' to produce even more hydrogen.

After a single 12-hour-day and 12-hour-night cycle, Pakrasi and his
team kept the lights on for a further 48 hours straight. During this time, the
microbes continued with their 'night-time' nitrogen fixation and hydrogen
production in the period that would normally have been dark, but made more fuel
for the process by photosynthesizing. The researchers found that under these
conditions the microbes adjusted their photosynthetic capacity to maximize
nitrogen fixation.

The amount of hydrogen produced in this way -- 150 micro moles per
milligram of chlorophyll per hour -- is the most ever recorded in natural
cyanobacteria under normal atmosperic conditions, says Pakrasi. If the bacteria
behaved in the same way in a litre of culture medium as they did in the 25
millilitres of medium used in the experiment, they would make just over 900 ml
of hydrogen in 48 hours -- the time taken for the experiment.

Natural high

"This is the most effective system published so far for hydrogen
production," says Oliver Lenz at HumboldtUniversity in Berlin, who works on the enzyme hydrogenase.
In his work, Lenz has grafted hydrogenase directly onto photosystem I, a
protein unit needed for photosynthesis. Naturally occurring bacteria can't
compete with such systems, with hydrogen production rates in Lenz's system
achieving greater volumes -- 3,000 micro mols of hydrogen per milligram of
chlorophyll per hour, Lenz says -- but the system remains untested in a natural
setting, and that's the advantage of Pakrasi's discovery. "I never expected
such high rates for a natural organism," Lenz adds. Synthetic approaches
such as Lenz's suffer from being short lived, Pakrasi says, often running out
of steam within hours, whereas the cyanobacteria "just keep going for
days".

Organisms other than cyanobacteria, such as the alga Chlamydomonas
reinhardtii, also produce hydrogen at similar rates, says Olaf Kruse of BielefeldUniversity
in Germany,
who works with the species. But these other microbes need strict anaerobic
conditions to work. Kruse is keen to see Pakrasi scale up his experiments to
check thatCyanothece 51142 works as well when cultured in larger volumes.
Pakrasi says that his team is about to begin this work, and has already moved
from 25 ml of culture to 200 ml with similar results.

At the moment, Cyanothece 51142 has small amounts of a hydrogenase that
eats up some of the hydrogen as it is produced. To make Cyanothece 51142 work
better, Lenz suggests genetically modifying the bacterium to contain a more
efficient hydrogenase enzyme, so less hydrogen is lost.

The work shows what an unmodified cyanobacterium is capable of, says
Pakrasi. There are at least 10 other strains of Cyanothece, and Pakrasi expects
these to work in a similar way. "One can -- and we have -- enhance the
rate by making genetic modifications to the system," he says.

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About Me

Apr 2017 - 4.1 Mil Pg Views, March 2013 - Posted my paper introducing CLOUD COSMOLOGY & NEUTRAL NEUTRINO rigorously described as the SPACE TIME PENDULUM, September 2010 I am pleased to report that my essay titled A NEW METRIC WITH APPLICATIONS TO PHYSICS AND SOLVING CERTAIN HIGHER ORDERED DIFFERENTIAL EQUATIONS' has been published in Physics Essays(AIP) and appeared in their June 2010 quarterly. 40 years ago I took an honors degree in applied mathematics from the University of Waterloo. My interest was Relativity and my last year there saw me complete a 900 level course under Hanno Rund on his work in relativity,as well as differential geometry(pure math) and of course analysis. I continued researching new ideas and knowledge since that time and I have prepared a book for publication titled Paradigms Shift&. I maintain my blog as a day book and research tool to retain data and record impressions and interpretations on material read. Do join my blog and receive Four items of interest daily Monday through Saturday.